Start the game and type any one of those cheats (without "") when playing the game.

Code Result
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"MONEYMONEY" get 1000$
"HITMENOW" Play as HITMAN
"JOBDONE" Current mission completed
"MAXPAYNE" Play as MAXPAYNE
"LIONARE" Always get 100% of health
"POLICECAR" Spawns a POLICE CAR